Communication device, program and communication control method

ABSTRACT

There is provided a communication device comprising: a detection unit that detects presence or absence of communication connection with a server storing data related to a communication environment of a communication area where a first communication service is provided; a data acquisition unit that acquires data related to a surrounding communication environment; and a determination unit that determines availability of usage of a second communication service using a part or whole of a spectrum assigned to the first communication service based on the data acquired by the data acquisition unit, wherein when communication connection with the server is not detected by the detection unit, the data acquisition unit senses a communication environment surrounding the communication device or receives data related to a communication environment from another communication device located near the communication device.

CROSS REFERENCE TO PRIOR APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/015,005 (filed on Aug. 30, 2013) and Ser. No. 12/686,740 (filed onJan. 13, 2010 and issued as U.S. Pat. No. 8,572,212 on Oct. 29, 2013),which claim priority to Japanese Patent Application No. 2009-009921(filed on Jan. 20, 2009), which are all hereby incorporated by referencein their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a communication device, a program and acommunication control method.

Description of the Related Art

Discussions have been taking place recently regarding secondary usage ofa spectrum assigned for primary usage to provide a secondarycommunication service depending on the use condition of the spectrum.For example, the standard specification for allowing an unused channelcontained in a spectrum of the U.S. digital TV broadcast (TV whitespaces) to be available for radio communication has been studied in theIEEE802.22 working group (“IEEE802.22 WG on WRANs”, [online], [Searchedon Jan. 5, 2009], cf. Internet <URL:http://www.ieee802.org/22/>).Further, according to the report from the Federal CommunicationsCommission (FCC) on November 2008, the discussions are directed towardpermitting secondary usage of TV white spaces by using specificcommunication devices that have been authorized by fulfilling a certaincriterion (“Second Report and Order and Memorandum Opinion and Order”,[online], [Searched on Jan. 5, 2009], cf. Internet<URL:http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-08-260A1.pdf>).In addition, there are moves, led by the EU, afoot to universallyallocate a dedicated control channel called the cognitive pilot channel(CPC) for making dynamic spectrum access (DSA). Technological studiesfor a secondary usage system that makes DSA are also being progressed inIEEE Standards Coordinating Committee (SCC) 41. Further, as anotherexample of secondary usage of a spectrum, there is a case where asecondary communication system is constructed using a simplercommunication protocol in a service area of a majority system that usesa non-licensed spectrum. For example, it is assumed that when a WiFi(registered trademark) system that uses an Industry-Science-Medical(ISM) band is a majority system, a secondary communication system isconstructed using another simple communication protocol in its servicearea.

In the implementation of secondary usage of a spectrum, it is necessaryto sense the surrounding communication environment in advance andconfirm that a communication service related to secondary usage (whichis referred to hereinafter as a second communication service) does notcause an adverse effect on a communication service related to primaryusage (which is referred to hereinafter as a first communicationservice).

SUMMARY OF THE INVENTION

However, when performing secondary usage of a spectrum, a device thatdetermines the availability of secondary usage cannot always sense thesurrounding communication environment accurately by itself. Although apossible approach is to sense the surrounding communication environmentin collaboration with other devices, there is a concern that the load ofsensing processing increases if the communication environment isuniformly sensed by a plurality of devices.

In light of the foregoing, it is desirable to provide a novel andimproved communication device, program and communication control methodcapable of controlling a method for sensing a communication environmentto determine the availability of secondary usage of a spectrum accordingto the state of communication connection.

According to an embodiment of the present invention, there is provided acommunication device including: a detection unit that detects presenceor absence of communication connection with a server storing datarelated to a communication environment of a communication area where afirst communication service is provided; a data acquisition unit thatacquires data related to a surrounding communication environment; and adetermination unit that determines availability of usage of a secondcommunication service using a part or whole of a spectrum assigned tothe first communication service based on the data acquired by the dataacquisition unit, wherein when communication connection with the serveris not detected by the detection unit, the data acquisition unit sensesa communication environment surrounding the communication device orreceives data related to a communication environment from anothercommunication device located near the communication device.

When communication connection with the server is detected, the detectionunit may further identify whether the communication connection is wiredconnection or wireless connection.

When wireless connection with the server is detected by the detectionunit, the data acquisition unit may acquire the data related to acommunication environment by sensing the communication environmentsurrounding the communication device.

When the data related to the communication environment surrounding thecommunication device sensed by the data acquisition unit does not meet aspecific criterion, the data acquisition unit may receive, from anothercommunication device located near the communication device, data relatedto a communication environment sensed by said another communicationdevice.

When wireless connection with the server is detected by the detectionunit, the data acquisition unit may instruct said another communicationdevice to perform sensing of a communication environment by using atechnique with a smaller load compared to when communication connectionwith the server is not detected by the detection unit.

The data acquisition unit may further receive data related to thecommunication environment surrounding the communication device from theserver.

When wired connection with the server is detected by the detection unit,the data acquisition unit may receive data related to the communicationenvironment surrounding the communication device from the server.

When communication connection with the server is not detected by thedetection unit and data obtained by sensing the communicationenvironment surrounding the communication device does not meet aspecific criterion, the data acquisition unit may receive data relatedto a communication environment from another communication device locatednear the communication device.

The data acquisition unit may change a range for acquiring data relatedto a communication environment depending on whether a device forpermitting usage of the second communication service has authority topermit usage of the second communication service permanently ortemporarily.

Data related to a communication environment may be received from aplurality of other communication devices located near the communicationdevice.

According to another embodiment of the present invention, there isprovided a program causing a computer controlling a communication deviceto implement functions including: a detection unit that detects presenceor absence of communication connection with a server storing datarelated to a communication environment of a communication area where afirst communication service is provided; a data acquisition unit thatacquires data related to a surrounding communication environment; and adetermination unit that determines availability of usage of a secondcommunication service using a part or whole of a spectrum assigned tothe first communication service based on the data acquired by the dataacquisition unit, wherein when communication connection with the serveris not detected by the detection unit, the data acquisition unit sensesa communication environment surrounding the communication device orreceives data related to a communication environment from anothercommunication device located near the communication device.

According to another embodiment of the present invention, there isprovided a communication control method in a communication deviceincluding the steps of: detecting presence or absence of communicationconnection with a server storing data related to a communicationenvironment of a communication area where a first communication serviceis provided; acquiring data related to a surrounding communicationenvironment; and determining availability of usage of a secondcommunication service using a part or whole of a spectrum assigned tothe first communication service based on the acquired data, wherein whencommunication connection with the server is not detected, the data isacquired in the communication device by sensing a communicationenvironment surrounding the communication device or receiving the datafrom another communication device located nearby.

According to the embodiments of the present invention described above,it is possible to provide a communication device, a program and acommunication control method capable of controlling a method for sensinga communication environment to determine the availability of secondaryusage of a spectrum according to the state of communication connection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of a hardware configurationof a communication device according to an embodiment.

FIG. 2 is a schematic view showing an example of a system configurationin which wired connection with a data server is available.

FIG. 3 is a schematic view showing another example of a systemconfiguration in which wired connection with a data server is available.

FIG. 4 is a schematic view showing an example of a system configurationin which wireless connection with a data server is available.

FIG. 5 is a schematic view showing another example of a systemconfiguration in which wireless connection with a data server isavailable.

FIG. 6 is a schematic view showing an example of a system configurationin which communication connection with a data server is unavailable.

FIG. 7 is a schematic view showing another example of a systemconfiguration in which communication connection with a data server isunavailable.

FIG. 8 is a schematic view showing a logical configuration of a controldevice according to an embodiment.

FIG. 9 is a flowchart showing an example of a flow of control processingaccording to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Preferred embodiments of the present invention will be describedhereinafter in the following order.

1. Functional Classification for Secondary Usage of Spectrum

2. Exemplary Hardware Configuration of Communication Device

3. Details of Control according to Configuration of Communication System

-   -   3-1. System Configuration in which Wired Connection is Available    -   3-2. System Configuration in which Wireless Connection is        Available    -   3-3. System Configuration in which No Communication Connection        is Available    -   3-4. Logical Configuration of Device    -   3-5. Flow of Processing

4. Example of Sensed Data

5. Summary

1. FUNCTIONAL CLASSIFICATION FOR SECONDARY USAGE OF SPECTRUM

Firstly, the principal functions (FC: Function Class) to be incorporatedinto communication devices that join a system in order to implementsecondary usage of a spectrum are listed below. A communication devicethat joins a system incorporates one or more than one of the sevenfunctions (FC1 to FC7) listed below.

FC1: Secondary communication authentication node

FC2: Primary communication relay node

FC3: Advanced determination node

FC4: Determination node

FC5: Smart sensor node

FC6: Sensor node

FC7: Communication node

[1-1. Secondary Communication Authentication Node (FC1)]

The secondary communication authentication node (FC1) permits start orextension of the second communication service in accordance with thespectrum policy when it is determined that secondary usage of a spectrumis available by the advanced determination node or the determinationnode, which are described later. The secondary communicationauthentication node may check whether a terminal identifier, anauthentication identifier, a device identifier, a sensor identifier orthe like which is transmitted from the advanced determination node orthe determination node is contained in a list of identifiers that havemade an unauthorized use of a frequency in the past, for example. If anyof the above identifiers is contained in the list of identifiers thathave made an unauthorized use, for example, the secondary communicationauthentication node can reject start or extension of the secondcommunication service. Further, if a base station that controls thetraffic of the first communication service is the secondarycommunication authentication node, the base station may refer to historyof user traffic or the like and grant permission for secondary usage fora time period or a place with many unoccupied channels. It is therebypossible to make some unoccupied channels open and enable effective useof a spectrum. Further, the secondary communication authentication nodemay generate, acquire or update information to be used for determinationabout the availability of secondary usage by the advanced determinationnode or the determination node and supply the information to theadvanced determination node or the determination node. The informationto be used for determination about the availability of secondary usagecontains community-based or service-area-based regulatory informationsuch as a power level usable for sensing and system information (forexample, band or bandwidth currently in use) provided by neighboringbase stations, for example. The secondary communication authenticationnode can thus serve as a so-called coordinator of the secondcommunication service.

There are two kinds of secondary communication authentication nodes: apermanent secondary communication authentication node and a temporarysecondary communication authentication node. The permanent secondarycommunication authentication node is a communication device that isauthorized to coordinate the second communication service because itmeets a predetermined criterion set by statute or the like. On the otherhand, the temporary secondary communication authentication node is acommunication device that receives authority from the permanentsecondary communication authentication node because it meets a specificcriterion according to a communication environment or the like andthereby temporarily makes coordination of the second communicationservice within the range of the granted authority (for example, within arange of the limited frequency channels or resource blocks, or within arange of a transmission power under a specific maximum value). Herein,“coordination” of a communication service may contain, for example,allocation of resources for the communication service. The temporarysecondary communication authentication node may, for example, performcollaborative resource allocation for a second communication service byexchanging scheduling information each other with the permanentsecondary communication authentication node.

[1-2. Primary Communication Relay Node (FC2)]

The primary communication relay node (FC2) serves as a pseudo basestation or access point that, when connected with a communicationnetwork related to primary usage (which is referred to hereinafter as afirst communication network), allows nearby nodes to use the firstcommunication service.

[1-3. Advanced Determination Node (FC3)]

The advanced determination node (FC3) determines whether extension of acommunication network related to secondary usage (which is referred tohereinafter as a second communication network) is available based on asecondary communication profile acquired from the determination node,which is described later. The secondary communication profile typicallycontains sensed data (including link data statistically calculated fromsensed data). The secondary communication profile may further containscheduling information for each of the second communication services.The secondary communication profile may further contain an identifier ofthe spectrum policy assigned to each determination node or the like. Forexample, the advanced determination node may determine that the secondcommunication network is extendable when a criterion for startingsecondary usage (a sensing level or a database) coincides with a nearbysecond communication network. Alternatively, the advanced determinationnode may determine that the second communication network is extendablewhen all networks satisfy the strictest sensing level. Further, theadvanced determination node may determine that the second communicationnetwork is extendable when a database is accessible by using a commonchannel between networks. Furthermore, when communication devices to beconnected with each other are included in two adjacent networks, theadvanced determination node may determine the availability of extensionof the second communication network with conditions that the purpose islimited to relaying or multi-hopping data between the communicationdevices. Furthermore, the advanced determination node may determine thatan extension of a second communication network is available, when it ispossible to raise the maximum transmission power without causing anadverse effect to the first communication service by utilizing ainterference control technology based on beam forming or transmissionpower control. If the advanced determination node determines thatextension of the second communication network is available, it requeststhe secondary communication authentication node to permit extension ofthe second communication network. Typically, the advanced determinationnode has a function of the determination node, which is described later,also. It should be noted that, when the advanced determination node andthe secondary communication authentication node exist on a physicallysame device, a communication between the advanced determination node andthe secondary communication authentication node is performed as acommunication between logical functions (or it may be omitted). On theother hand, when the advanced determination node and the secondarycommunication authentication node exist on physically different devices,a communication between the advanced determination node and thesecondary communication authentication node is performed using eitherwireless ling or wired link. The wireless link herein may be a wirelesslink based on the first communication service, for example. The wiredlink herein may be a link either on a private network (for example, corenetwork) or on a public network (for example, ADSL).

[1-4. Determination Node (FC4)]

The determination node (FC4) determines whether secondary usage of aspectrum is available according to the spectrum policy based on senseddata sensed or acquired by the smart sensor node or the sensor node,which are described later. For example, the determination node maydetermine that secondary usage of a spectrum is available when a powerlevel sensing result of a spectrum as a target of secondary usage islower than a power sensing level defined in the above-describedregulatory information. Alternatively, the determination node maydetermine that secondary usage of a spectrum is available when secondaryusage is permitted for a spectrum as a target of secondary usage as aresult of making inquiry to a data server, which is described later, forexample. Further, the determination node may determine that secondaryusage of a spectrum is available when a power level sensing result of aspectrum as a target of secondary usage is lower than a power sensinglevel indicated by data obtained from the data server described above,for example. The power level sensing result of a spectrum as a target ofsecondary usage may be an averaged value of A/D sampling output values,for example. If the determination node determines that secondary usageof a spectrum is available, it requests the secondary communicationauthentication node to permit start of the second communication service.Then, if start of the second communication service is permitted by thesecondary communication authentication node, the determination nodeinvites users of the second communication service by transmitting abeacon to nearby communication devices, for example, and starts thesecond communication service. Beacons transmitted by the determinationnode may be used by the nearby communication devices for detection,synchronization, acquisition of system information and the likeregarding the second communication service. For example, primarysynchronization signal and secondary synchronization signal, signals onPBCH (Physical Broadcast Channel) or the like are an example of theabove-described beacons. The determination node thus serves as an enginefor cognitive radio that switches from the first communication serviceto the second communication service. Further, the determination nodegenerates the secondary communication profile in response to aninstruction from the above-described advanced determination node andtransmits the profile to the advanced determination node. It should benoted that, similarly to the above description about the advanceddetermination node, a communication between the determination node andthe secondary communication authentication node is also performed as acommunication between logical functions (In a case that they are on thesame device. But the above communication processes may be omitted) or asa communication using wireless ling or wired link (In a case that theyare on different devices.).

In communication control processing according to an embodiment of thepresent invention which is described later, a sensing method of acommunication environment to be used for determination of start orextension of a secondary usage system is decided principally by theadvanced determination node or the determination node described above. Asensing method of a communication environment depends on which patternof communication connection is available for the advanced determinationnode or the determination node to communicate with a server thatintegrally stores data related to a communication environment in aservice area of the first communication service. Details of specificcontrol of the sensing method are further described later.

[1-5. Smart Sensor Node (FC5)]

The smart sensor node (FC5) acquires sensed data related to acommunication environment stored in each node from the sensor node orthe smart sensor node located in the nearby vicinity of its own device.The smart sensor node may further add sensed data sensed in its owndevice to the acquired sensed data (or use the sensed data sensed in itsown device only). The smart sensor node thus serves as an extendedsensor capable of acquiring sensed data necessary for determination ofsecondary usage in collaboration with the nearby nodes. Further, thesmart sensor node transmits the stored sensed data in response to aninstruction from the smart sensor node or the determination node.

[1-6. Sensor Node (FC6)]

The sensor node (FC6) senses the communication environment surroundingits own device and generates sensed data. As described later in detail,the sensed data is typically data indicating the surroundingcommunication environment relating to the first communication service.For example, a power level or energy of received signals or schedulinginformation of the first communication service may be used as dataindicating the surrounding communication environment. The sensor nodethus serves as a sensor that generates sensed data necessary fordetermination of secondary usage. Further, the sensor node transmits thegenerated sensed data in response to an instruction from the smartsensor node or the determination node.

[1-7. Communication Node (FC7)]

The communication node (FC7) performs communication using the secondcommunication service when secondary usage of a spectrum is available.The communication node thus serves as a general communication device. Acommunication protocol used for the second communication service may bea desired communication protocol such as IEEE802.11a/b/g/n/s, Zigbee orWiMedia, for example.

[1-8. Scope of the Term “Secondary Usage”]

In this specification, the term “secondary usage” typically meansutilization of an additional or alternative communication service (asecond communication service) using a part or whole of a spectrumassigned to a first communication service as described above. In thiscontext about the meaning of the term “secondary usage”, the firstcommunication service and the second communication service may beservices of different types or the same type. The services of differenttypes may be selected from services such as digital TV broadcastingservice, satellite communication service, mobile communication service,wireless LAN access service, P2P (Peer To Peer) connection service andthe like. On the other hand, services of the same type may contain, forexample, a relationship between a service of macro-cell provided by acommunication carrier and a service of femto-cell operated by users orMVNO (Mobile Virtual Network Operator). Additionally, services of thesame type may contain, for example, a relationship between a serviceprovided by a base station of a communication service according toWiMAX, LTE (Long Term Evolution), LTE-A (LTE-Advanced) or the like and aservice provided by relay station (relay node) to cover a spectrum hole.Further, a second communication service may be a service utilizing aplurality of fragmentary frequency bands aggregated using spectrumaggregation technology. Furthermore, a second communication service maybe a supplementary communication service provided by femto-cells, relaystations or small or medium sized base stations for smaller service areathan normal sized base stations within a service area of a normal sizedbase station. The subject matter of each embodiment described in thisspecification is applicable to every type of mode of such secondaryusages.

2. EXEMPLARY HARDWARE CONFIGURATION OF COMMUNICATION DEVICE

A hardware configuration of a communication device that incorporates oneor more than one of the functions FC1 to FC7 listed in the previoussection is described hereinbelow.

FIG. 1 is a block diagram showing an example of a hardware configurationof the communication device described above. The communication deviceshown in FIG. 1 by way of illustration includes a central processingunit (CPU) 22, read only memory (ROM) 24, random access memory (RAM) 26,a bus 30, an input/output interface 32, an input device 40, an outputdevice 42, a storage device 44, a communication interface (I/F) 46 and adrive 48.

In FIG. 1, the CPU 22 controls the operation of a general-purposecomputer as a whole. The ROM 24 stores programs executed by the CPU 22,data and so on. The RAM 26 temporarily stores a program or data duringexecution of processing by the CPU 22.

The CPU 22, the ROM 24 and the RAM 26 are connected with one anotherthrough the bus 30. The input/output interface 32 is also connected tothe bus 30.

The input/output interface 32 connects the CPU 22, the ROM 24 and theRAM 26 with the input device 40, the output device 42, the storagedevice 44, the communication interface 46 and the drive 48.

The input device 40 receives an instruction or information input from auser through a button, a switch, a lever, a mouse, a keyboard, a touchpanel or the like, for example. The output device 42 outputs informationto a user through a display device such as a cathode ray tube (CRT), aliquid crystal display or an organic light emitting diode (OLED), alight emitting device such as a lamp, or an audio output device such asa speaker, for example. The storage device 44 is made up of a hard diskdrive or flash memory, for example, and stores programs, data and so on.The communication interface 46 mediates communication processing for thefirst communication service or the second communication service. Aremovable medium 49 is loaded to the drive 48 according to need.

Each of the functions FC1 to FC7 listed in the previous section may beimplemented as software, for example. In the case where each function isimplemented as software, for example, a program constituting software isstored in the ROM 24 or the storage device 44 shown in FIG. 1, loaded tothe RAM 26 upon execution and executed by the CPU 22. Alternatively,each function may be implemented as hardware by using a dedicatedprocessor which is additionally mounted to the communication device.

3. DETAILS OF CONTROL ACCORDING TO CONFIGURATION OF COMMUNICATION SYSTEM

As described above, in an embodiment of the present invention, a sensingmethod of a communication environment that is used for determination ofstart or extension of secondary usage is controlled according to thepresence or absence of communication connection between a serverintegrally storing data related to a communication environment and thedetermination node or the advanced determination node and a pattern ofthe communication connection. In this section, an exemplary systemconfiguration of a secondary usage system is presented for each patternof communication connection, and a logical configuration of acommunication device that performs control according to the pattern ofcommunication connection is described.

[3-1. System Configuration in which Wired Connection is Available]

(First System Configuration)

FIG. 2 is a schematic view showing an example of a system configurationin which wired connection is available between a server integrallystoring data related to a communication environment and thedetermination node. A communication system having the systemconfiguration shown therein is referred to as a communication system 1a. Circled numerals in FIG. 2 correspond to the numbers of the functions(FC) described above.

Referring to FIG. 2, the communication system 1 a includes a basestation 100, three communication devices 110 and a sensor device 120.The three communication devices 110 and the sensor device 120 arelocated inside an area 102 where communication with the base station 100is possible. The base station 100 is connected to a server 10 through anetwork 12, which is a wired network.

The server 10 is a server that integrally stores data related to acommunication environment of the first communication service provided bythe base station 100. The server 10 may serve also as a device thatprovides the first communication service by using the base station 100.The first communication service may be a digital TV broadcast service,for example, or another kind of communication service. The data storedin the server 10 may contain data about a frequency currently in use foreach location in a communication area, use history data of a frequencyfor each location, prediction data related to a condition of trafficpredicted from the use history data or the like, for example. The server10 can supply such data related to a communication environment (which isreferred to hereinafter as server data) in response to a request fromthe advanced determination node or the determination node describedabove.

The base station 100 provides the above-described first communicationservice to the devices located inside the area 102. Further, the basestation 100 coordinates secondary usage of an unused part (or whole) ofthe spectrum assigned to the first communication service. To be morespecific, the base station 100 operates as the secondary communicationauthentication node (FC1) and the determination node (FC4) describedabove. Further, the base station 100 may operate as the sensor node(FC6). Specifically, the base station 100 first acquires data related tothe surrounding communication environment by a method decided by controlprocessing, which is described later. Next, based on the acquired data,the base station 100 determines whether secondary usage of a spectrum isavailable according to the spectrum policy. If the base station 100determines that secondary usage is available based on the sensed data,it starts a communication service related to secondary usage, which is asecond communication service. The base station 100 in this case is apermanent secondary communication authentication node that meets apredetermined criterion set by statute or the like.

On the other hand, the communication devices 110 operate as thecommunication node (FC7) described above. Specifically, thecommunication devices 110 transmit and receive radio signals to and fromthe base station 100.

The sensor device 120 operates as the sensor node (FC6) described above.Specifically, in response to an instruction from the base station 100,the sensor device 120 can generate sensed data related to acommunication environment by sensing the communication environmentsurrounding its own device and then transmit the generated sensed datato the base station 100.

(Second System Configuration)

FIG. 3 is a schematic view showing another example of a systemconfiguration in which wired connection is available between a serverintegrally storing data related to a communication environment and thedetermination node. A communication system having the systemconfiguration shown therein is referred to as a communication system 1b.

Referring to FIG. 3, the communication system 1 b includes a basestation 100, three sensor devices 120 and a smart sensor device 130. Thethree sensor devices 120 and the smart sensor device 130 are locatedinside an area 102 where communication with the base station 100 ispossible. The base station 100 is connected to a server 10 through anetwork 12, which is a wired network.

In the communication system 1 b, in response to an instruction from thesmart sensor device 130 located in the nearby vicinity, the sensordevices 120 can transmit sensed data generated by sensing thecommunication environment surrounding their own devices to the smartsensor device 130.

On the other hand, the smart sensor device 130 operates as the smartsensor node (FC5) described above. Specifically, the smart sensor device130 can give an instruction for sensing of a communication environmentto the sensor devices 120 in the nearby vicinity, acquire sensed datafrom the sensor devices 120 and then transmit the acquired sensed datato the base station 100. At this time, the smart sensor device 130 mayadd sensed data obtained by sensing the surrounding communicationenvironment of its own to the acquired data.

If wired connection is available between the server 10 and the basestation 100 as in the communication system 1 a or 1 b, it is preferredthat the base station 100 serving as the determination node receivesdata related to a communication environment from the server 10 and usesthe data. It is thereby possible to make determination about start (orextension) of secondary usage of a spectrum without increasing the loadof distributed sensing, for example.

[3-2. System Configuration in which Wireless Connection is Available]

A system configuration in which wired connection is unavailable and onlywireless connection is available with the server 10 in the determinationnode (or the smart sensor node) is described hereinbelow.

(Third System Configuration)

FIG. 4 is a schematic view showing an example of a system configurationin which wireless connection is available between a server integrallystoring data related to a communication environment and thedetermination node. A communication system having the systemconfiguration shown therein is referred to as a communication system 2a.

Referring to FIG. 4, the communication system 2 a includes a basestation 200, two sensor devices 220, two sensor devices 222, a smartsensor device 230, and a determination device 240. The two sensordevices 220, the smart sensor device 230 and the determination device240 are located inside an area 202 where communication with the basestation 200 is possible. The base station 200 is connected to a server10 through a network 12, which is a wired network.

The base station 200 can provide the first communication service to thedevices located inside the area 202. Further, the base station 200 cantemporarily grant authority for permitting secondary usage of an unusedpart (or whole) of the spectrum assigned to the first communicationservice to the determination device 240, which is described later,according to a communication environment. Thus, the base station 200operates as the permanent secondary communication authentication node(FC1) described above. Instead of that the base station 200 is thesecondary communication authentication node, another node in the network12 may be the secondary communication authentication node, and the basestation 200 may mediate grant of authority from the node to thedetermination device 240.

The sensor devices 220 operate as the sensor node (FC6) described above.Specifically, in response to an instruction from the smart sensor device230 or the determination device 240, the sensor devices 220 can generatesensed data related to a communication environment by sensing thecommunication environment surrounding their own devices and transmit thedata. The sensor devices 222 also operate as the sensor node (FC6)described above. Specifically, in response to an instruction from thesmart sensor device 230 or the determination device 240, the sensordevices 222 can generate sensed data related to a communicationenvironment by sensing the communication environment surrounding theirown devices and transmit the data.

The smart sensor device 230 operates as the smart sensor node (FC5)described above. Specifically, the smart sensor device 230 can give aninstruction for sensing a communication environment to the sensordevices 220 or 222 located in the nearby vicinity, acquire sensed dataand transmit the acquired sensed data to the determination device 240.At this time, the smart sensor device 230 may add sensed data obtainedby sensing the surrounding communication environment of its own to theacquired data.

The determination device 240 operates as the primary communication relaynode (FC2) and the determination node (FC4) described above. Further,the determination device 240 can operate as the temporary secondarycommunication authentication node (FC1) described above. Specifically,the determination device 240 first acquires data related to thesurrounding communication environment by a method decided by controlprocessing, which is described later. Next, based on the acquired data,the determination device 240 determines whether provision of the secondcommunication service is available using a spectrum which is notactually used in the spectrum assigned to the first communicationservice according to the spectrum policy. If the determination device240 determines from the sensed data that provision of the secondcommunication service is available, the determination device 240requests the base station 200 for temporary grant of authority forpermitting start of the second communication service. At this time, thedetermination device 240 transmits the acquired sensed data,additionally obtained location data of its own device or the like to thebase station 200. If the authority is granted in accordance with thetransmitted data, the determination device 240 starts the secondcommunication service with a communication device located in the nearbyvicinity (e.g. an area 204) of its own device.

Further, the determination device 240 operates as the primarycommunication relay node and thus serves as a pseudo base station oraccess point for the first communication service, and it can relay acommunication packet corresponding to the first communication servicewhich is transmitted from the sensor device 222, for example, to thebase station 200.

(Fourth System Configuration)

FIG. 5 is a schematic view showing another example of a systemconfiguration in which wireless connection is available between a serverintegrally storing data related to a communication environment and thedetermination node. A communication system having the systemconfiguration shown therein is referred to as a communication system 2b.

Referring to FIG. 5, the communication system 2 b includes a basestation 200, five sensor devices 220, two smart sensor devices 230, adetermination device 240 and an advanced determination device 250. Thebase station 200 is connected to a server 10 through a network 12, whichis a wired network.

In the communication system 2 b, the two smart sensor devices 230acquire sensed data from the sensor devices 220 located in the nearbyvicinity and transmit the acquired sensed data respectively in responseto an instruction from the determination device 240 or the advanceddetermination device 250.

The determination device 240 acquires data related to the surroundingcommunication environment by a method decided by control processing,which is described later, and determines whether start of secondaryusage of a spectrum is available or not, as described above withreference to FIG. 4. Further, in response to a request from the advanceddetermination device 250, the determination device 240 can create asecondary communication profile containing the acquired sensed data,link data calculated from the sensed data, the spectrum policy or thelike and transmit the profile to the advanced determination device 250.

The advanced determination device 250 operates as the advanceddetermination node (FC3) described above. Further, the advanceddetermination device 250 can operate as the temporary secondarycommunication authentication node (FC1) described above. Specifically,the advanced determination device 250 first gives instruction fortransmission of the secondary communication profile to the determinationdevice 240.

The advanced determination device 250 then acquires data related to thesurrounding communication environment by a method decided by controlprocessing, which is described later, and determines whether extensionof the second communication network is available. If the advanceddetermination device 250 determines that extension of the secondcommunication network is available, the advanced determination device250 requests the base station 200 for temporary grant of authority forpermitting extension of the second communication network. At this time,the advanced determination device 250 transmits a determination resultindicating that extension of the second communication network isavailable, data used for the determination or the like to the basestation 200. If the authority is granted in accordance with the data orthe like, the advanced determination device 250 starts provision of thesecond communication service with the extended network range tocommunication devices located in the nearby vicinity of its own deviceand the determination device 240.

In the communication system 2 a or 2 b, wired connection is unavailableand only wireless connection is available with the server 10 in thedetermination device 240 or the advanced determination device 250. Inthis case, it is preferred that the determination device 240 or theadvanced determination device 250 receives data related to acommunication environment from the server 10 and uses the data, andfurther performs sensing in its own device also. If a sensing result inits own device is insufficient, distributed sensing may be performed byusing the sensor devices 220 or the smart sensor devices 230. It isthereby possible to make determination about start (or extension) ofsecondary usage of a spectrum without making the heavy load due to datadownloading on wireless connection with the server 10. In this example,the case where the determination device 240 and the advanceddetermination device 250 are the temporary secondary communicationauthentication nodes is described. However, the same is applicable tothe case where the determination device 240 or the advanceddetermination device 250 is the permanent secondary communicationauthentication node and only wireless connection is available with theserver 10.

[3-3. System Configuration in which No Communication Connection isAvailable]

The case where wired connection and wireless connection are bothunavailable with the server 10 in the determination node (or the smartsensor node) is described hereinbelow.

(Fifth System Configuration)

FIG. 6 is a schematic view showing an example of a system configurationin which both of wired connection and wireless connection are notavailable between a server integrally storing data related to acommunication environment and the determination node. A communicationsystem having the system configuration shown therein is referred to as acommunication system 3 a.

Referring to FIG. 6, the communication system 3 a includes a basestation 300, two sensor devices 320, two sensor devices 322, a smartsensor device 330, and a determination device 340. The base station 300is connected to a server 10 through a network 12, which is a wirednetwork.

The base station 300 can provide the first communication service to thedevices located inside the area 302.

The sensor devices 320 operate as the sensor node (FC6) described above.Specifically, in response to an instruction from the smart sensor device330 or the determination device 340, the sensor devices 320 can generatesensed data related to a communication environment by sensing thecommunication environment surrounding their own devices and thentransmit the data. The sensor devices 322 also operate as the sensornode (FC6) described above. Specifically, in response to an instructionfrom the smart sensor device 330 or the determination device 340, thesensor devices 322 can generate sensed data related to a communicationenvironment by sensing the communication environment surrounding theirown devices and transmit the data.

The smart sensor device 330 operates as the smart sensor node (FC5)described above. Specifically, the smart sensor device 330 can give aninstruction for sensing a communication environment to the sensordevices 320 or 322 located in the nearby vicinity, acquire sensed dataand transmit the acquired sensed data to the determination device 340.At this time, the smart sensor device 330 may add sensed data obtainedby sensing the surrounding communication environment of its own to theacquired data.

The determination device 340 operates as the permanent secondarycommunication authentication node (FC1) and the determination node (FC4)described above. Specifically, the determination device 340 firstacquires data related to the surrounding communication environment by amethod decided by control processing, which is described later. In thecase of the communication system 3 a, however, because the determinationdevice 340 is incapable of connection with the server 10 by wiredconnection or wireless connection, the determination device 340 acquiressensed data related to a communication environment from its own deviceor the sensor devices 320 or the smart sensor device 330 in the nearbyvicinity. Next, based on the acquired data, the determination device 340determines whether provision of the second communication service isavailable using a spectrum which is not actually used in the spectrumassigned to the first communication service according to the spectrumpolicy. If the determination device 340 determines from the acquireddata that provision of the second communication service is available,the determination device 340 starts the second communication servicewith a communication device located in the nearby vicinity (e.g. an area304) of its own device. In the communication system 3 a, thedetermination device 340 is not necessarily located inside thecommunication area 302 where the first communication service isprovided.

(Sixth System Configuration)

FIG. 7 is a schematic view showing another example of a systemconfiguration in which both of wired connection and wireless connectionare not available between a server integrally storing data related to acommunication environment and the determination node. A communicationsystem having the system configuration shown therein is referred to as acommunication system 3 b.

Referring to FIG. 7, the communication system 3 b includes a basestation 300, five sensor devices 320, a smart sensor device 330, adetermination device 340 and an advanced determination device 350. Thebase station 300 is connected to a server 10 through a network 12, whichis a wired network.

In the communication system 3 b, the sensor devices 320 can transmitsensed data generated by sensing the communication environmentsurrounding their own devices in response to an instruction from thesmart sensor device 330, the determination device 340 or the advanceddetermination device 350

The smart sensor device 330 can transmit sensed data acquired from thesensor devices 320 in the nearby vicinity to the determination device340 in response to an instruction from the determination device 340. Thesmart sensor device 330 may further add sensed data obtained by sensingthe surrounding communication environment of its own to the acquireddata.

The determination device 340 acquires data related to the surroundingcommunication environment by a method decided by control processing,which is described later, and determines whether start of secondaryusage of a spectrum is available or not, as described above withreference to FIG. 6. Further, in response to a request from the advanceddetermination device 350, the determination device 340 can create asecondary communication profile containing the acquired sensed data,link data calculated from the sensed data, the spectrum policy or thelike and transmit the profile to the advanced determination device 350.

The advanced determination device 350 operates as the permanentsecondary communication authentication node (FC1) and the advanceddetermination node (FC3) described above. Specifically, the advanceddetermination device 350 gives instruction for transmission of thesecondary communication profile to the determination device 340. Theadvanced determination device 350 further acquires data related to thesurrounding communication environment by a method decided by controlprocessing, which is described later, and determines whether extensionof the second communication network is available. If the advanceddetermination device 350 determines that extension of the secondcommunication network is available, the advanced determination device350 starts provision of the second communication service with theextended network range to communication devices located in the nearbyvicinity of its own device and the determination device 340. In thecommunication system 3 b, the determination device 340 or the advanceddetermination device 350 is not necessarily located inside thecommunication area 302 where the first communication service isprovided.

In the communication system 3 a or 3 b, wired connection and wirelessconnection with the server 10 are not available in the determinationdevice 340 or the advanced determination device 350. In this case, it ispreferred that the determination device 340 or the advanceddetermination device 350 senses the surrounding communicationenvironment of its own and further performs distributed sensing by usingthe sensor devices 320 or the smart sensor device 330. For example, thedetermination device 340 or the advanced determination device 350 mayperform distributed sensing by using the sensor devices 320 or the smartsensor device 330 when sensed data obtained by sensing in its own devicedoes not meet a specific criterion. The specific criterion can be set inadvance by using a parameter such as radio signal energy, a noise powerlevel, a noise ratio or an error rate, for example. It is therebypossible to make determination about start (or extension) of secondaryusage of a spectrum without depending on reception of data from theserver 10.

As is understood from the foregoing description, according to anembodiment of the present invention, a sensing method of a communicationenvironment to be used for determination of start or extension ofsecondary usage is selected appropriately according to the presence orabsence of communication connection with a server integrally storingdata related to a communication environment and a pattern of thecommunication connection. In the following section, a logicalconfiguration of a communication device that executes control of asensing method of a communication environment is described specifically.

[3-4. Logical Configuration of Device]

FIG. 8 is a block diagram showing a logical configuration of functionsprincipally related to control of sensing of a communicationenvironment, among the functions of the base station 100, thedetermination device 240, the advanced determination device 250, thedetermination device 340 or the advanced determination device 350described above.

Referring to FIG. 8, each device (which is referred to hereinafter as acontrol device) includes a communication unit 170, a connectiondetection unit 182, a data acquisition unit 184 and a determination unit186.

The communication unit 170 mediates communication connection between thecontrol device and the server 10 and communication connection betweenthe control device and another communication device (e.g. thecommunication device 110, the sensor device 120, the smart sensor device130 etc.). In the case of the above-described communication system 1 aor 1 b, for example, communication connection between the control deviceand the server 10 through the communication unit 170 is implemented aswired connection by a desired communication protocol such as Ethernet(registered trademark) or FDDI. In the case of the above-describedcommunication system 2 a or 2 b, for example, communication connectionbetween the control device and the server 10 through the communicationunit 170 is implemented as wireless connection by a desiredcommunication protocol such as IEEE802.11a/b/g/n/s, Zigbee or WiMedia,for example. Further, in the case of the above-described communicationsystem 3 a or 3 b, for example, communication connection between thecontrol device and the server 10 through the communication unit 170 isnot implemented.

The connection detection unit 182 detects the presence or absence ofcommunication connection between the server 10 that integrally storesdata related to a communication environment in a service area of thefirst communication service and the control device. After detectingcommunication connection with the server 10, the connection detectionunit 182 further identifies whether the detected communicationconnection is wired connection or wireless connection.

The data acquisition unit 184 acquires data related to a communicationenvironment in the nearby vicinity of the control device (e.g. insidethe communication area 102, 204, 206, 304 or 306).

In the case where wired connection is available between the server 10and the control device, the data acquisition unit 184 preferablyreceives (downloads) the data related to the communication environmentsurrounding the control device from the server 10. The data receivablefrom the server 10 is the above-described server data stored in theserver 10. Specifically, data of a frequency currently in use for eachlocation in a specific communication area, use history data of afrequency for each location, predicted data related to a condition oftraffic predicted from the use history data or the like can be receivedfrom the server 10. The data acquisition unit 184 may sense additionaldata by communicating with another communication device or may furtherreceive sensed data of a communication environment acquired by anothercommunication device.

In the case where wired connection is unavailable and only wirelessconnection is available between the server 10 and the control device,the data acquisition unit 184 preferably receives the data related to acommunication environment from the server 10 and further performssensing in its own device also. In this case, it is possible to reducethe amount of data received from the server 10 and thereby reduce theload on wireless connection. Further, if the accuracy of data related tothe communication environment surrounding its own device which is sensedby itself, the amount of data, the frequency of sensing or the like doesnot meet a predetermined criterion set in advance, the data acquisitionunit 184 may additionally receive sensed data related to a communicationenvironment from another communication device located in the vicinity.In this case also, the data acquisition unit 184 can make determinationabout start (or extension) of secondary usage by combining the datareceived from the server 10 and the data sensed by itself. It is therebypossible to reduce the frequency of sensing or the amount of datarequited for distributed sensing compared to the case wherecommunication connection with the server 10 is not detected, therebyreducing the load caused by distributed sensing.

In the case where wired connection and wireless connection are bothunavailable between the server 10 and the control device, the dataacquisition unit 184 preferably performs sensing in its own device andfurther performs distributed sensing over a wider area by using anothercommunication device. In this case, the control device transmits aninstruction for sensing of a communication environment or acquisition ofsensed data to the sensor devices 320 and the smart sensor device 330shown in FIG. 6 or 7, for example. The control device then receivessensed data of a communication environment from each device that hasreceived the instruction. Because the sensed data in a wider range isrelayed and integrated by the plurality of sensor devices 320 and thesmart sensor device 330, it is possible to increase the accuracy ofdetermination about start (or extension) of secondary usage of aspectrum without receiving the server data from the server 10.

Further, the data acquisition unit 184 may change the rang ofdistributed sensing depending on whether the secondary communicationauthentication node is the permanent secondary communicationauthentication node or the temporary secondary communicationauthentication node, for example. If it is the permanent secondarycommunication authentication node, distributed sensing in a narrow rangemay be executed, and if it is the temporary secondary communicationauthentication node, distributed sensing in a wide range may beexecuted, for example. The distributed sensing in a narrow rangecorresponds to distributed sensing without need of relay or multi-hop ofsensed data as in the communication system 1 a shown in FIG. 2, forexample. On the other hand, the distributed sensing in a wide rangecorresponds to distributed sensing with need of relay or multi-hop ofsensed data as in the communication system 1 b shown in FIG. 3 or thecommunication system 2 b shown in FIG. 5, for example.

The determination unit 186 determines the availability of usage of thesecond communication service that uses a part or whole of the spectrumassigned to the first communication service according to the spectrumpolicy based on the data acquired by the data acquisition unit 184 asdescribed above.

[3-5. Flow of Processing]

FIG. 9 is a flowchart showing an example of a flow of determinationprocessing about the availability of secondary usage of a spectrum bythe determination node (or the advanced determination node) constitutingthe configuration shown in FIG. 8.

Referring to FIG. 9, the presence or absence of communication connectionwith a server that stores data related to a communication environment ina service area of the first communication service and a connectionpattern (wired or wireless) are detected by the connection detectionunit 182 (S102). Then, a detection result of communication connection isoutput from the connection detection unit 182 to the data acquisitionunit 184.

Next, the presence or absence of communication connection with theserver is determined by the data acquisition unit 184 (S104). If thereis no communication connection with the server, the process proceeds tothe step S108. On the other hand, if there is communication connectionwith the server, it is determined by the data acquisition unit 184whether the pattern of the communication connection is wired connectionor wireless connection (S106). If the pattern of the communicationconnection is wired connection, the process proceeds to the step S112.If, on the other hand, the pattern of the communication connection iswireless connection, the process proceeds to the step S110.

In the step S108, it is further determined by the data acquisition unit184 whether the secondary communication authentication node is thepermanent secondary communication authentication node (S108). If thesecondary communication authentication node is the permanent secondarycommunication authentication node, the process proceeds to the stepS116. On the other hand, if the secondary communication authenticationnode is the temporary secondary communication authentication node, theprocess proceeds to the step S118.

In the step S110 also, it is further determined by the data acquisitionunit 184 whether the secondary communication authentication node is thepermanent secondary communication authentication node (S110). If thesecondary communication authentication node is the permanent secondarycommunication authentication node, the process proceeds to the stepS114. On the other hand, if the secondary communication authenticationnode is the temporary secondary communication authentication node, theprocess proceeds to the step S116.

In the step S112, a sensing method with the small load is executed bythe data acquisition unit 184 by using wired connection with the serverthat stores data related to a communication environment (S112).Specifically, as described earlier, the data related to a communicationenvironment which is integrally stored in the server 10 is downloaded bythe data acquisition unit 184, for example. Further, supplementarysensing of a communication environment may be performed by the dataacquisition unit 184, for example.

In the step S114, a sensing method with the intermediate load isexecuted by the data acquisition unit 184 (S114). For example, the datarelated to a communication environment which is integrally stored in theserver 10 is downloaded, and sensing of a communication environment andacquisition of sensed data from another communication device areperformed by the data acquisition unit 184.

In the step S116, distributed sensing in a narrow range is executed bythe data acquisition unit 184 (S116). For example, the data acquisitionunit 184 gives an instruction for sensing of a communication environmentto other communication devices located in the vicinity, so that senseddata is acquired from each device. The data acquisition unit 184 mayfirst sense the surrounding communication environment in its own deviceand, when a sensing result does not satisfy a specific criterion,execute distributed sensing in a narrow range, for example.

In the step S118, distributed sensing in a wide range is executed by thedata acquisition unit 184 (S118). For example, the data acquisition unit184 gives an instruction for sensing of a communication environment andacquisition of sensed data to other communication devices located in thevicinity. Receiving the instruction, each communication device acquiressensed data from yet other communication devices located in thevicinity. Thus, in this case, sensed data related to a communicationenvironment is relayed in a wider range compared to that in the stepS116.

After that, the availability of usage (start or extension) of the secondcommunication service that uses a part or whole of the spectrum of thefirst communication service is determined by the determination unit 186based on the data related to a communication environment which isacquired by any method of the above-described steps S112 to S118 (S120).

In FIG. 9, the case of controlling a sensing method of a communicationenvironment by dividing it into four sensing levels of S112 to S118according to the state of communication connection is described.However, any of the sensing levels of S112 to S118 may be omitted, or adifferent sensing level may be added. For example, three sensing levelsof S112, S114 or S116 and S118 may be used by omitting the determinationwhether the secondary communication authentication node is permanent inS108 and S110.

Further, in FIG. 9, a flow of determination processing as to theavailability of secondary usage of a spectrum by the determination node(or the advanced determination node) is described. However, theprocessing of S102 to S118 related to control of a sensing method of acommunication environment shown in FIG. 9 may be executed by thesecondary communication authentication node, the smart sensor node, thesensor node or the like, for example.

4. EXAMPLE OF SENSED DATA

According to an embodiment of the present invention, the dataacquisition unit 184 shown in FIG. 8 by way of illustration acquires thesensed data related to a communication environment that is sensed by thesensor node or the smart sensor node described above. The targetcommunication resources of sensing by the sensor node or the smartsensor node are communication resources, which there is a possibilitythat they are used by the first communication service, and representedby frequency channels, resource blocks, codes or the like. Which rangeof the communication resources should be sensed is, for example,determined by monitoring the downlink broadcast channel of the firstcommunication service (such as PBCH of LTE or the like). The sensed datamay contain an identifier of a device which has sensed a communicationenvironment and a sensing result, and may further contain location dataof a device acquired using a global positioning system (GPS), a kind ofa sensing algorithm, a time stamp or the like. Further, link data thatis obtained by statistically summarizing the sensed data, schedulinginformation indicating surrounding communication environment regardingthe first communication service and the like can be contained in thesensed data in a broad sense.

The location data of a device is data indicating the location of adevice which has sensed a communication environment at the time ofsensing, for example. The location data is used for determination aboutthe availability of secondary usage of a spectrum by the determinationnode (or the advanced determination node), for example. Specifically,the determination node downloads a location information database whichis externally prepared in advance to its own device. Data of thelocation information database may be data that is common to the datastored in the server 10 described above or data that is storedseparately. The location information database contains channelassignment of the first communication service, channel usage history orthe like in association with the location data. Thus, the determinationnode can retrieve channel assignment or channel usage history from thelocation information database by using the location data as a key, forexample, and thereby evaluate the possibility that the secondary usagecauses an adverse effect on the first communication service. Instead ofdownloading the location information database to its own device inadvance, the determination node may make inquiry to an external databaseby using the location data as a key at the time of determining theavailability of secondary usage, for example.

The kind of a sensing algorithm indicates what kind of value is to besensed (or have been sensed), such as radio signal energy, a noise powerlevel, a noise ratio (e.g. SNR or CNR) or an error rate (e.g. BER orPER), for example.

The sensing result contains the value of the sensing result according tothe kind of a sensing algorithm described above. The value of thesensing result may be represented by soft bit (soft decision value) orhard bit (hard decision value). For example, it is preferred that thedetermination node (or the advanced determination node) represents thesensing result to be transmitted to the secondary communicationauthentication node by hard bit. In this case, a result of determiningthe availability of secondary usage according to the sensed value isrepresented by a logical value such as “0” or “1”. This enables adecrease in traffic between nodes. On the other hand, the sensing resultto be transmitted from the sensor node (or the smart sensor node) to thedetermination node (or the advanced determination node) is typicallyrepresented by soft bit.

The time stamp contains time when sensing of a communication environmentis started, time when sensing of a communication environment ends or thelike, for example.

In the case of transmitting or receiving the above-described sensed databetween the equal nodes such as between the advanced determinationnodes, an autonomous distributed communication protocol such asIEEE802.11s or WiMedia may be used. Alternatively, a hierarchicalmanagement communication protocol such as Zigbee may be used accordingto control of the node which has transmitted a beacon first. If theautonomous distributed communication protocol is used between nodes atthe same level in the above-described function classifications FC1 toFC7, it is possible to easily change the topology of the secondary usagesystem in accordance with the location of devices. On the other hand, itis preferred to use the hierarchical management communication protocolaccording to control of a higher-order node between nodes at differentlevels in the function classifications FC1 to FC7.

5. SUMMARY

Control processing related to a sensing method of a communicationenvironment for determination about the availability of secondary usageof a spectrum according to an embodiment is described above in detailwith reference to FIGS. 1 to 9. According to the technique described inthis specification, a method for sensing a communication environment todetermine the availability of secondary usage of a spectrum iscontrolled according to the presence or absence of communicationconnection with a server integrally storing data related to acommunication environment and a connection pattern. It is therebypossible to improve the accuracy of sensing of a communicationenvironment at the time of start or extension of secondary usage orreduce the load for sensing.

The subject matter of each embodiment described in this specification isapplicable to various types of modes of secondary usage. For example, asdescribed above, it can be said that operation of relay node orfemto-cell to cover a spectrum hole of the first communication serviceis a mode of secondary usage of spectrum. Further, the relationshipbetween any one or more of macro-cell, RRH (Remote Radio Head), Hotzone,relay node, femto-cell and the like may form a mode of secondary usageof spectrum (such as heterogeneous network).

Although preferred embodiments of the present invention are described indetail above with reference to the drawings, the present invention isnot limited thereto. It should be understood by those skilled in the artthat various modifications, combinations, sub-combinations andalterations may occur depending on design requirements and other factorsinsofar as they are within the scope of the appended claims or theequivalents thereof.

What is claimed is:
 1. A communication device comprising: circuitryconfigured to detect presence or absence of communication connectionbetween the communication device and a server, the server storing datarelated to a communication environment of a communication area where afirst communication service is provided; acquire data related to asurrounding communication environment; and determine availability ofusage of a second communication service using a part or whole of aspectrum assigned to the first communication service based on theacquired data, wherein when communication connection between thecommunication device and the server is not detected, the data isacquired in the communication device by sensing a communicationenvironment surrounding the communication device or receiving the datafrom another communication device located near the communication device,wherein when communication connection between the communication deviceand the server is detected, the circuitry is further configured toidentify whether the communication connection is a wired connection or awireless connection, and wherein when the communication connection isidentified as a wireless connection, the circuitry is further configuredto instruct the another communication device to perform sensing of acommunication environment by using a technique with a smaller loadcompared to when communication connection between the communicationdevice and the server is not detected.
 2. The communication deviceaccording to claim 1, wherein when the communication connection isidentified as the wireless connection and the server is detected, thecircuitry is further configured to acquire the data related to acommunication environment by sensing the communication environmentsurrounding the communication device.
 3. The communication deviceaccording to claim 1, wherein when the data related to the communicationenvironment surrounding the communication device sensed by the dataacquisition unit does not meet a specific criterion, the circuitry isfurther configured to receive, from the another communication devicelocated near the communication device, data related to a communicationenvironment sensed by the another communication device.
 4. Thecommunication device according to claim 1, wherein the circuitry isfurther configured to receive data related to the communicationenvironment surrounding the communication device from the server.
 5. Thecommunication device according to claim 1, wherein when wired connectionbetween the communication device and the server is detected, thecircuitry is further configured to receive data related to thecommunication environment surrounding the communication device from theserver.
 6. The communication device according to claim 1, wherein whencommunication connection between the communication device and the serveris not detected and data obtained by sensing the communicationenvironment surrounding the communication device does not meet aspecific criterion, the circuitry is further configured to receive datarelated to a communication environment from another communication devicelocated near the communication device.
 7. The communication deviceaccording to claim 1, wherein the circuitry is further configured tochange a range for acquiring data related to a communication environmentdepending on whether a device for permitting usage of the secondcommunication service has authority to permit usage of the secondcommunication service permanently or temporarily.
 8. The communicationdevice according to claim 1, wherein data related to a communicationenvironment is received from a plurality of other communication deviceslocated near the communication device.
 9. The communication deviceaccording to claim 1, wherein the circuitry is further configured toinitiate a transmission of a beacon to a third communication devicelocated near the communication device, to permit usage of the secondcommunication service.
 10. A non-transitory computer-readable mediumhaving embodied thereon a program, which when executed by a computercontrolling a communication device causes the communication device toexecute a method, the method comprising: detecting presence or absenceof communication connection between the communication device and aserver, the server storing data related to a communication environmentof a communication area where a first communication service is provided;acquiring data related to a surrounding communication environment; anddetermining availability of usage of a second communication serviceusing a part or whole of a spectrum assigned to the first communicationservice based on the acquired data, wherein when communicationconnection between the communication device and the server is notdetected, the data is acquired in the communication device by sensing acommunication environment surrounding the communication device orreceiving the data from another communication device located near thecommunication device, wherein when communication connection between thecommunication device and the server is detected, the communicationconnection is identified as a wired connection or a wireless connection,and wherein when the communication connection is identified as awireless connection, the another communication device is instructed toperform sensing of a communication environment by using a technique witha smaller load compared to when communication connection between thecommunication device and the server is not detected.
 11. A communicationcontrol method in a communication device, the method comprising:detecting presence or absence of communication connection between thecommunication device and a server, the server storing data related to acommunication environment of a communication area where a firstcommunication service is provided; acquiring data related to asurrounding communication environment; and determining availability ofusage of a second communication service using a part or whole of aspectrum assigned to the first communication service based on theacquired data, wherein when communication connection between thecommunication device and the server is not detected, the data isacquired in the communication device by sensing a communicationenvironment surrounding the communication device or receiving the datafrom another communication device located near the communication device,wherein when communication connection between the communication deviceand the server is detected, the communication connection is identifiedas a wired connection or a wireless connection, and wherein when thecommunication connection is identified as a wireless connection, theanother communication device is instructed to perform sensing of acommunication environment by using a technique with a smaller loadcompared to when communication connection between the communicationdevice and the server is not detected.